Perhaps it’s just part of a larger trend of paying less for everything outside of Anbar Province, but the Bush Administration seems to have embraced the idea of congestion charges for freeways and dense urban areas. If the feds are totally behind this idea, it could be the best friend public transportation ever had, even if the money collected only pays for highway maintenance.

That’s because of the refrain I keep hearing from transit advocates: Freeways aren’t free. They cost billions of dollars to build and maintain, which to most motorists is an invisible cost until they cross a toll bridge or start working at Caltrans.

A lot of big numbers, but nearly everyone who backed this thing in the last election called it a “down-payment” on fixing a problem that’s going to cost a lot more to fix.

So what’s this got to do with congestion fees, aka tolls? It could directly help public transportation, as has been widely proposed, including here in the Bay Area. BART, AC Transit or other agencies could receive a portion of toll proceeds from special “HOT (high-occupancy toll)” lanes for people to pay to bypass traffic even if they’re not carpooling.

But the more critical benefit for public transportation is that it would bring the cost of highway construction and maintenance into the glaring light of “Pay up, bud!”

Public transit subsidies that pay for about half of many bus and rail trips are one of the biggest handicaps for people who want to elevate transit from an adjunct to driving and charity for the car-less.

If every dime of highway maintenance or, say, the debt service on the transportation bond had to be wrung out of motorists driving down state Highway 24 or U.S. Highway 101, a lot more people would be taking the bus to work while looking for a job closer to home. That obviously wouldn’t happen, because general tax dollars would continue to pump money into the highway system even as universal FasTrak boxes racked up the miles every commuter drove to work.

At least then both sides in the transit-driving debate would have equal reason to moan about the other mode not paying for itself.